Santa Monica, CA Coastal Erosion Rate
What USGS measures 3.5 miles northwest of Santa Monica, CA
3.5 miles northwest of Santa Monica, CA, the coast is advancing, not retreating, at a measured 0.21 feet a year, sediment accumulating faster than any erosion USGS recorded here. At that rate, the shoreline has gained roughly 2.1 feet over the last decade.
The grain of this number
This is a roughly 3.5-mile stretch of coast, not one address or parcel - USGS's own transects run every few hundred feet, but that's finer than any one property needs, so this page reports the stretch nearest Santa Monica, CA. Centered near 34.04°N, 118.55°W. USGS's California assessment last surveyed this stretch through 1852-2016, computing the rate with its LRR method. Other US regions were surveyed in different years, sometimes decades apart, so this page states its own rather than implying one national vintage.
25 years at this rate
Holding the 0.21 ft/yr accretion rate 3.5 miles northwest of Santa Monica, CA for 25 years would add roughly 5 feet of shoreline, again assuming nothing about the local sediment supply changes.
How solid is this number
This reading comes from 96 individual transects averaged together, 22% of which measured erosion rather than growth. USGS's confidence interval here is ±0.2 ft/yr. Among the 1211 US coastal segments with a measurable trend, this one ranks 932 for erosion, 1 being the fastest-retreating coast in the dataset. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. Siesta Key, FL sits at national rank 1178 for growth (2.82 ft/yr), one reference point among the 1211 scored segments, 2179 miles from here. 1.9 miles away, Santa Monica, CA is the nearest other measured stretch: accretion (beach growing) at 1.21 ft/yr.
Not this whole stretch, just Santa Monica itself: the Coastal Change Hazards Portal is USGS's own live version of this data.